1 /*
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 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 4  *
 5  * This code is free software; you can redistribute it and/or modify it
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 7  * published by the Free Software Foundation.  Oracle designates this
 8  * particular file as subject to the "Classpath" exception as provided
 9  * by Oracle in the LICENSE file that accompanied this code.
10  *
11  * This code is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
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19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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24  */
25 
26 package java.lang.foreign;
27 
28 import java.util.List;
29 import jdk.internal.javac.PreviewFeature;
30 
31 /**
32  * A compound layout that is an aggregation of multiple, heterogeneous <em>member layouts</em>. There are two ways in which member layouts
33  * can be combined: if member layouts are laid out one after the other, the resulting group layout is a
34  * {@linkplain StructLayout struct layout}; conversely, if all member layouts are laid out at the same starting offset,
35  * the resulting group layout is a {@linkplain UnionLayout union layout}.
36  *
37  * @implSpec
38  * This class is immutable, thread-safe and <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>.
39  *
40  * @sealedGraph
41  * @since 19
42  */
43 @PreviewFeature(feature=PreviewFeature.Feature.FOREIGN)
44 public sealed interface GroupLayout extends MemoryLayout permits StructLayout, UnionLayout {
45 
46     /**
47      * {@return the member layouts of this group layout}
48      *
49      * @apiNote the order in which member layouts are returned is the same order in which member layouts have
50      * been passed to one of the group layout factory methods (see {@link MemoryLayout#structLayout(MemoryLayout...)},
51      * {@link MemoryLayout#unionLayout(MemoryLayout...)}).
52      */
53     List<MemoryLayout> memberLayouts();
54 
55     /**
56      * {@inheritDoc}
57      */
58     @Override
59     GroupLayout withName(String name);
60 
61     /**
62      * {@inheritDoc}
63      */
64     @Override
65     GroupLayout withoutName();
66 
67     /**
68      * {@inheritDoc}
69      * @throws IllegalArgumentException {@inheritDoc}
70      * @throws IllegalArgumentException if {@code byteAlignment} is less than {@code M}, where {@code M} is the maximum alignment
71      * constraint in any of the member layouts associated with this group layout.
72      */
73     @Override
74     GroupLayout withByteAlignment(long byteAlignment);
75 }